Such a power supplying device is, e.g., known from the United States patent application US 2007/0182367 A1. Said patent application describes a portable inductive power device for charging battery operated electronic devices. The power device uses a pad with an array of coils and an AC power source to create an alternating magnetic field. The alternating magnetic field is used for charging the electronic device lying on the pad, close to the AC powered coils. In an embodiment (FIG. 16), each coil in the array has its own little segment within which it is free to move laterally. Thus, this embodiment may be considered to use an array of fixed coil segments instead of an array of fixed coils. The coils may comprise a permanent magnet for controlling the lateral movements.
One of the problems of this known power supplying device is that it needs a lot of coils and corresponding driving electronics. Each coil is connected to a power source with a wire, which restricts the freedom of movement for the coil and limits the possibilities to use multiple coils in combination. These problems make the known device less suitable for use in large area applications. For a charging apparatus for portable electronic devices, the area size may not be very important, but for other applications scalability may be an important aspect. For example, a table or wall surface capable of supplying power to a freely movable lamp may be quite large. When applying the known technology to an entire wall, a lot of coils and additional electronics are required.